fix: handle undefined GITHUB_WORKSPACE in version file path

Author: cadamsdev

dist/index.js

@@ -119,7 +119,7 @@ function resolveVersionInput() {
         core.warning('Both version and version-file inputs are specified, only version will be used');
     }
     if (versionFileInput) {
-        const versionFilePath = path.join(process.env.GITHUB_WORKSPACE, versionFileInput);
+        const versionFilePath = path.join(process.env.GITHUB_WORKSPACE ?? '', versionFileInput);
         if (!fs.existsSync(versionFilePath)) {
             throw new Error(`The specified v version file at: ${versionFilePath} does not exist`);
         }

dist/index.js.map

@@ -102,7 +102,7 @@ function resolveVersionInput(): string {
 
   if (versionFileInput) {
     const versionFilePath = path.join(
-      process.env.GITHUB_WORKSPACE!,
+      process.env.GITHUB_WORKSPACE ?? '',
       versionFileInput
     )
     if (!fs.existsSync(versionFilePath)) {